Re: P3 amplitude calibration

[Mike Scott-7]

Given Alan's plans, I detect a need for an XG3 now that he wants to make the
P3 amplitude calibration per band.

 

The XG3 could be ten band 160 through 6M accurate 50 uV and 1uV source.
Actually I might want something other than 1 uV as that is an awkward value
between S3 and S2.

 

So a 10-band source with -73 dBm and -103 dBm outputs might be better
because -103 dBm would be S-4 for those who like 6dB per S-unit and S-3 for
those who want  5dB per S-unit.

 

AE6WA

Mike Scott

Tarzana, CA

 

----------------------------------------------------------------------------
-------------------

Alan N1AL said:

On my list of features to add is amplitude calibration, similar to the

S-meter calibration in the K3.  I plan to make it per-band to account

for variations in the K3 RF chain and to separately measure the gain of

the K3's preamp and the attenuator.  This level of accuracy isn't really

needed for normal operation of a radio, but as an ex-Agilent/HP engineer

I'm kind of a perfectionist when it comes to measurement accuracy.  :=)

 

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[Alan Bloom]

Actually, you don't need to calibrate the P3 at different levels.  The
ADC is linear within a tiny fraction of a dB over its whole range, so
once you calibrate at one level, all levels should be accurate.

But you bring up a good point about needing a different signal source
for each band.  I guess I should include a "global" calibration that
applies to any bands that haven't been calibrated.

Alan N1AL


On Mon, 2010-08-30 at 13:36 -0700, Mike Scott wrote:

> Given Alan's plans, I detect a need for an XG3 now that he wants to make the
> P3 amplitude calibration per band.
>
>  
>
> The XG3 could be ten band 160 through 6M accurate 50 uV and 1uV source.
> Actually I might want something other than 1 uV as that is an awkward value
> between S3 and S2.
>
>  
>
> So a 10-band source with -73 dBm and -103 dBm outputs might be better
> because -103 dBm would be S-4 for those who like 6dB per S-unit and S-3 for
> those who want  5dB per S-unit.
>
>  
>
> AE6WA
>
> Mike Scott
>
> Tarzana, CA
>
>  
>
> ----------------------------------------------------------------------------
> -------------------
>
> Alan N1AL said:
>
> On my list of features to add is amplitude calibration, similar to the
>
> S-meter calibration in the K3.  I plan to make it per-band to account
>
> for variations in the K3 RF chain and to separately measure the gain of
>
> the K3's preamp and the attenuator.  This level of accuracy isn't really
>
> needed for normal operation of a radio, but as an ex-Agilent/HP engineer
>
> I'm kind of a perfectionist when it comes to measurement accuracy.  :=)
>
>  
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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